Yasuhiko Endo

Malignant solitary fibrous tumour of the peritoneum

Solitary fibrous tumour, formerly known as localized fibrous mesothelioma, may arise from the peritoneum in rare instances, whereas it commonly appears as a pleural neoplasm [1,2]. Solitary fibrous tumour of the peritoneum occurs in both sexes and in all age groups, but predominantly affects those between the 4th and 7th decades of life [1,2]. Unlike diffuse mesotheliomas, solitary fibrous tumour shows no relationship to asbestos exposure [1]. It tends to be asymptomatic or produces minor symptoms such as vague abdominal complaints [1]. Benign and malignant forms of the tumour occur, the benign variant being three to four times more common than the malignant. Solitary fibrous tumour of the peritoneum can be identified as a large mass [1,2], and needs to be distinguished from gynaecological tumours on imaging studies. We report here a case of malignant solitary fibrous tumour of the peritoneum. Computed tomography (CT) and magnetic resonance (MR) imaging findings are described.

Carcinosarcoma of the uterus with extensive neuroectodermal differentiation

A case of uterine carcinosarcoma with extensive neuroectodermal differentiation occurring in a 54‐year‐old woman is described. Microscopically, the endometrial tumour was predominantly composed of a sheet‐like proliferation of small‐ and medium‐sized cells. These cells were characterized by fibrillary cytoplasmic processes, rosette‐like formations, perivascular palisading patterns, and immunoreactivity for glial fibrillary acidic protein, synaptophysin, leu 7 and neuron‐specific enolase. In limited areas, features of conventional carcinosarcoma, including squamous cell carcinoma, leiomyosarcoma and islands of the above mentioned small‐to medium‐sized cells that were intermingled, were observed. The tumour was aneuploid by flow cytometry. The patient is alive with tumour for three months. It is suggested that at least some cases of uterine primitive neuroectodermal tumour may be explained by one‐sided neuroectodermal development within a carcinosarcoma.

Atypical polypoid adenomyomas of the uterus

We performed a clinicopathological immunohistochemical, ultrastructural, and flow cytometric study on six cases of atypical polypoid adenomyoma of the uterus including one with an adenocarcinoma within it. The tumours occurred in nulliparous women aged 22–48 years (average, 33.0 years); three arose in the uterine corpus, and three in the endocervix. Histologically, they were composed of endometrial glands admixed with a stromal component of interlacing bundles of smooth muscle cells. The glands exhibited varying degrees of architectural and cytological atypia. Most of the stromal cells showed strong staining for HHF35, alpha‐smooth muscle actin, and vimentin, and some cells contained desmin. Electronmicroscopy, in one case, confirmed the presence of a well‐differentiated smooth muscle component. The stromal component may arise as a result of extensive metaplasia of endometrial stromal cells. Uninvolved endometrium showed ciliated cell metaplasia in three patients, and atypical complex hyperplasia in two. One patient had a well‐differentiated adenocarcinoma of endometrioid type arising in an endocervical atypical polypoid adenomyoma. All tumours had a diploid DNA content and relatively small S phase fraction (average, 6.23%). The follow‐up periods ranged from 4 to 42 months (average, 13.5 months), and all patients were alive and well. Although the histogenesis of atypical polypoid adenomyoma of the uterus remains uncertain, it is suggested that it may arise because of oestrogen‐related factors.

Calcifying fibrous pseudotumor.

A case of calcifying fibrous pseudotumor arising In the lngune of a 20‐year‐old Japanese female Is described. The patient had a well‐circumscrlbed subcutaneous mass measuring 2.0 cm In greatest diameter, which had been present for 3 months. Mlcroscoplcally. the tumor was not encapsulated but well defined. The tumor was composed largely of dense interwoven bundles of collagen. Uniform, elongated spindle cells were scattered among the collagenous bundles and showed a wavy pattern. Lymphoid follicles with germinal centers and an infiltration of lymphocytes and plasma cells wore intermingled. The tumor was characterized by the presonce of micracalcifications, chiefly dystrophic calcifications, throughout the Iesion. The spindle cells were diffusely positive for vimentin and α‐smooth muscle actin. They were uniformly nagative for desmin, muscle specific actin HHF35, frctor‐VII related antigen, S‐100 protein. neurofilament, cytokeratin CAM5.2, CD34, and CD31. By flow cytometry the tumor had a diplold DNA content with S‐phase fractions of 2.5%. The patient was well with no evidence of disease 2 months after excision.

Dumbbell‐shaped leiomyosarcoma of the inferior vena cava with foci of rhabdoid changes and osteoclast‐type giant cells

An inferior vena cava (IVC) tumor was incidentally found in a 67‐year‐old Japanese man. The resected tumor was lobulated and multinodular, measuring 14.0 × 6.5 × 7.0 cm, showing a dumbbell‐shaped appearance with a central constriction. The tumor showed both intra‐ and extra‐luminal growth. The tumor was primarily composed of well‐differentiated leiomyosarcoma. Spindle tumor cells in the well‐differentiated area were positive for vimentin, muscle actin, α‐smooth muscle actin, and desmin. Foci of rhabdoid cells and osteoclast‐type multinucleated giant cells were also found. Rhabdoid cells ultrastructurally had paranuclear aggregates or whorls of intermediate filaments that were positive for vimentin, low molecular weight cytokeratin, and desmin. Osteoclast‐type multinucleated giant cells were positive for only CD68 antigen, suggesting a reactive histiocytic lineage. To the best of our knowledge, this is the first case of IVC leiomyosarcoma accompanied by both rhabdoid tumor cells and osteoclast‐type reactive multinucleated giant cells. These unusual features should be kept in mind in the diagnosis of dumbbell‐shaped retroperitoneal tumors that involve the IVC.

SMALL CELL CARCINOMA OF THE OVARY : A CASE REPORT OF LARGE CELL VARIANT

An extremely rare case of large cell variant of ovarian small cell carcinoma is described. A 34‐year‐old woman (gravid 1. para 1) had a unilateral ovarian mass measuring 17 cm in great at diameter and a metastasis lesion in the omentum. Microscopically, the tumor showed a diffuse arrangement of large, closely packed epithelial cells with abundant eosino‐philic cytoplasm and large nuclei with prominent nucleoli. The tumor cells also were arranged in follicle‐like and trabe‐cular structures and cords. Immunohlstochemically, many tumor cells were diffusely positive for epithelial membrane antigen and some cells contained cytokeratin CAM5.2, valentine, neurofiiament, neuron‐specific enoiase, or alpha‐1 antitrypsn. However, no specific IIneage was detected. The tumor was aneuploid by flow cytometry. The patient received chemotherapy postoperatively. However, the patient showed metastases in the Inguinal and retruperitoneal lymph nodes. The aerum calcium level, which was not measured preoperatively, was mildly elevated postoperatively. The patient was well with no evidence of disease 17 months after diagnosis. This tumor must be distinguished from other primary or metelltatic ‘undifferentiated’ neoplasms, especially ovarian small cell carcinoma of pulmonary type and granulosa cell tumor.

Small cell neuroendocrine carcinoma of the ovary

A 64-year-old woman (gravida 0, para 0) had a unilateral ovarian mass measuring 14 cm in its greatest diameter, which was mostly solid. Microscopically, the tumour was characterized by two predominant proliferating patterns: a carcinoid-like pattern with trabecular, tubular, glandular, or insular arrangements and a closely packed nesting pattern with central coagulation necrosis and occasional glandular arrangements. These two patterns were intermingled, and numerous mitotic figures were present. Electron microscopy showed neurosecretory granules in the cells, which were argyrophilic and positive for neuroendocrine markers (chromogranin, leu 7, neuron-specific enolase, and synaptophysin). The tumour was aneuploid by flow cytometry. The patient received chemotherapy postoperatively, developed brain and multiple bone metastases and died of disease 10 months after surgery. This tumour must be distinguished from other small cell neoplasms, especially ovarian small cell carcinoma of the hypercalcaemic type.

Gynandroblastoma of the ovary : a case report with an immunohistochemical and ultrastructural study

An ovarian gynandroblastoma in a 60-year-old woman is described. The cut-surface of the right ovary showed multiple macrofollicles separated by white fibrous tissues and multiple ill-defined yellowish nodules. The tumour consisted of substantial amount of a granulosa cell element and a Sertoli cell element with intermingled Leydig cells. Immunohistochemically, the tumour cells in both the granulosa cell and Sertoli cell elements were positive for cytokeratin CAM5.2. The granulòsa cell element showed strong membrane staining of Ewings sarcoma antigen 013 and the Sertoli cell element was focally positive. Vimentin was observed in both the Sertoli cell element and the granulosa cells. Both elements and the Leydig cells were uniformly negative for epithelial membrane antigen, muscle specific actin, CD31 and CD34. The tumour was aneuploid by flow cytometry. The patient was well with no evidence of tumour five months after surgery.

Mixed tumour of the vagina

A 33‐year‐old Japanese woman presented with a polypoid 2.5 × 2.5 × 1.9 cm mass located in the posterior wall of the lower vagina. Microscopically, the tumour was composed of benign epithelial and stromal‐type elements. Predominant epithelial elements were mucinous glands with squamous metaplasia and islands of mature squamous epithelium. The stromal‐type cells showed reticular or short fascicular patterns with a transition to the epithelial elements. There was no dual epithelial‐myoepithelial combination in the glands as seen in so‐called mixed tumours (pleomorphic adenomas) of the salivary gland. Immunohistochemically, the epithelial elements were strongly positive for cytokeratin, PKK1 and epithelial membrane antigen, while the stromal‐type cells co‐expressed PKK1 and vimentin. Staining for S‐100 protein, muscle actin, alpha‐smooth muscle actin, desmin, and CD34 was uniformly negative in the tumour cells. The DNA pattern was diploid. The patient is alive and well without recurrence for 50 months after excision. These results indicate that an epithelial cell proliferation, probably of the remnant vestibular gland, plays a major role in the development of mixed tumours of the vagina.

Atypical Adenoma of the Thyroid: A Clinicopathologic and Flow Cytometric DNA Study in Comparison with Other Follicular Neoplasms

A clinicopathologic and DNA flow cytometric study was performed on seven patients (three males, four females) with atypical adenoma of the thyroid gland, using formalin‐fixed paraffin‐embedded tissues. The results were compared with those of 30 follicular adenomas and 13 follicular carcinomas. The patients ranged in age from 32 to 74 years (mean: 55.8 years), and the mean follow‐up period was 11.0 years. All patients except two who died of other diseases were free of thyroid disease after initial surgery. It showed that there was no evidence of clinical cancer in this follow‐up study of patients operated on for atypical adenomas. Four of the atypical adenomas were diploid, two were aneuploid, and one was tetraploid. Twenty‐seven of the 30 follicular adenomas were diploid. Three patients with aneuploid follicular adenoma were free of disease. Of the 13 follicular carcinomas with a mean follow up period of 6.9 years, five were diploid, seven were aneuploid, and one was tetraploid. Two patients with aneuploid follicular carcinoma and one with diploid carcinoma developed lung metastases, and one patient each with diploid and aneuploid follicular carcinoma died of disease. There was no significant correlation between histologic features, ploidy status and prognosis among follicular carcinomas. The results of this study suggest that DNA flow cytometric analysis is not a useful tool for predicting the clinical behavior of follicular neoplasms. Acta Pathol Jpn 42: 632–638, 1992.